Bolt tensile-load calculator
Estimate the minimum tensile (breaking) load of a metric bolt. Load = tensile stress area (mm²) × grade tensile strength (MPa) ÷ 1000. Stress areas per ISO 898-1 coarse pitch.
Min. tensile (breaking) load
— kN
— kgf
Proof load (working ceiling)
— kN
Stress area — mm² · pitch — mm
This is the minimum breaking load. Safe working / clamp loads are far lower — typically 60–75% of proof load. Apply your own safety factor for critical joints.
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